Approval granted for Hazelwood ash ponds

The Hazelwood Rehabilitation Project will meet its best environmental practice guideline obligations when it caps its redundant onsite ash ponds.

Hazelwood Ash Pond 1 (HAP1), HAP2a, HAP4, Asbestos Landfill No 3 and the Hazelwood Ash Retention Area (HARA) on the floor of the mine, like all landfills onsite, are licensed by the Environment Protection Authority (EPA). As they are now closed, EPA legislation requires ENGIE Hazelwood to cap these landfills to a specific standard as part of their closure and rehabilitation.

Hazelwood Project Environmental Manager Regulatory, Ross Brooker, said it was the first time ENGIE had gone through this process under the current EPA legislation.

Ash ponds were used to receive coal ash, a by-product from the electricity generation process.

“A number of older ash landfills, specifically HAP2 and HAP3, were successfully closed and rehabilitated some years ago,” Brooker said.

“The cap design and approval process for this current project will take well over 18 months, with a great deal of work required to design the specifications which include material type and depth of capping. This is separate and ahead of the actual cap construction on each of the separate landfills.

“The cap construction phase in itself is also highly regulated, with stringent and complex QA/QC process to be followed. Cap construction will be completed within two years of the final EPA approval of the cap design.”

The approved capping design for the landfills will be a combination of clay, synthetic clays and topsoil. The final design will require approval by an EPA auditor who then monitors the project to ensure the capping is built to EPA specifications.

Brooker said work on capping HAP2a and Asbestos Landfill No 3 would start when the new earthworks season began in early November this year. HAP1 will be used as a depository for the safe disposal of asbestos from power plant demolition, so capping will start in 2021, following the completion of the asbestos removal process.

The timing of capping the HARA has not yet been finalised but is expected to be in 2019/2020.